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1.
Pakistan is an agricultural country, yet it is facing a serious threat due to the shortage of water resources and degradation of the agricultural land by the pollution of industrial effluents. A limited number of the current industries are equipped with proper operating treatment plants. Generally, the untreated effluents are disposed off to the open environment which is used for irrigation purposes. Therefore, vegetables and crops grown around the industrial areas is a major potential source of metal poisoning which pose a serious risk to the general public. Hence, study of the toxicity level in vegetables and crops is highly desirable. In this regard, systematic studies have been carried out to determine concentration levels of toxic elements in the samples of vegetables, crops, effluents and soil collected from the industrial areas of the Faisalabad. After processing, these samples were analyzed using neutron activation analysis and atomic absorption spectrometric techniques. The highest concentrations of toxic metals were observed for As (2.73 ± 0.34) in cabbage, Cd (1.5 ± 0.1), Ni (5.1 ± 0.9) and Pb (4.3 ± 0.2) in corn, Co (0.65 ± 0.02), and Sb (0.09 ± 0.01) in carrot, Cr (9.63 ± 1.3), Mn (46.5 ± 4.2) and Se (1.03 ± 0.1) in millet, Cu (11.3 ± 1.1) in tomato vegetables and crop samples. Although, the observed toxicity levels in vegetables and crop samples were higher than those grown in non-industrial areas, yet these toxicity levels are within the safe recommended limits.  相似文献   

2.
Photon induced X-ray fluorescence is used at a medium sized Greek industrial city, to detect trace elements with 20≤Z≤40 in airborn particulates collected on filter papers.  相似文献   

3.
The physical, chemical and biological characteristics of industrial and municipal wastewater effluents in the United States are limited in National Pollutant Discharge Elimination System (NPDES) permits. Toxicity reduction evaluations (TREs) involving fractionation of wastewater effluents, biomonitoring for aquatic toxicity and determinations of specific chemicals are conducted when adverse effects on water quality are detected during routine biomonitoring as required by the NPDES permit. However, certain fractionation techniques are incompatible with subsequent testing for aquatic toxicity. The effect of various schemes for fractionation of wastewater effluent on biomonitoring with freshwater Cladocerans (Daphnia magna, Daphnia pulex, Ceriodaphnia dubia or Ceriodaphnia reticulata) is reviewed. Solid-phase extraction (SPE) is discussed as a chromatographic technique used for the selective fractionation of wastewater effluents during toxicity reduction evaluation.  相似文献   

4.
Scientists are interested in knowing more about the control of sources which contribute to environmental pollution. Air pollution has two main sources: anthropogenic and natural sources. The natural contributions to environmental pollution can be assessed, but cannot be totally controlled. while the emissions from the anthropogenic sources can be controlled. These air pollutants can be dispersed and transferred by winds in the atmosphere. The focus area of this study is the Mediterranean basin. The most important winds in this area are the land and sea breezes. Scanning Electron Microscopy (SEM) was applied to characterize the morphology of the PM10 samples in order to identify possible emission sources for the occuring pollution. Energy Dispersive X-ray Spectroscopy (EDS) was performed for the elemental analysis and chemical characterization of the PM10 samples. The analysis showed that the PM10 samples can be divided into three different groups: the samples containing mineral phases, the compounds from combustion processes and the particles emitted from high-temperature processes.   相似文献   

5.
Air particulate matter (PM) was collected in two size fractions using stacked filter units (SFUs) provided by the International Atomic Energy Agency (IAEA) from the industrial area of Islamabad. Nucleopore polycarbonate filters were used for collecting from Oct 98 to Jun 99 the particulate matter in coarse and fine size fractions. The samples were characterized by the instrumental neutron activation analysis (INAA). About 33 elements were quantified using different irradiation and counting protocols.  相似文献   

6.
In order to estimate the bioaccessibility of metals from mussel tissues, an in vitro physiologically based extraction test was applied to simulate the human gastrointestinal conditions. The samples were subjected to human body temperature, and Ag, Co, Cr, Cu, Mn, Ni, Pb and Sn were sequentially extracted with simulated gastric solution, followed by extraction with a simulated intestinal solution. Both gastric and intestinal extracted solutions and microwave-digested residue were analysed by ICP-MS. The procedure was applied to a certified reference material NIST 2977 (mussel tissue) to prove the accuracy of the method. Some mussel tissue samples from Northern Spain were subjected to this procedure to determine their metal content and their metal oral bioaccessibility.  相似文献   

7.
Amorphous TiO2, synthesized from TiCl4 and diluted NH3 solution, was characterized by X-ray diffraction spectrometry, UV–Vis diffused reflectance spectroscopy, Fourier-transformed infrared spectroscopy, and scanning electron microscopy. The powder exhibited high specific surface area at 508 m2/g as measured by the Brunauer-Emmett-Teller method. The pH at point of zero charge of the as-prepared amorphous TiO2 was determined by the pH drift method to be 6.8. The product was studied for its sorption efficiency using two dyes—crystal violet (CV) and malachite green (MG). Studies on the effects of various sorption parameters (contact time, TiO2 dosage, pH of solution, and initial concentration of dye) were carried out in order to find the optimum adsorption conditions for which the results were: contact time ~30 min, TiO2 dosage ~0.05–0.1 g, pH 7–9, and initial concentration <1 × 10?4 M. The adsorption data were analyzed and fitted better with the Langmuir model than the Freundlich model. The maximum adsorption capacities obtained from the Langmuir model were 0.4979 and 0.4075 mmol dye/g TiO2 for CV and MG dye, respectively. In addition, the regeneration and the recyclability of the prepared amorphous TiO2 were also studied. The used adsorbent should be regenerated 10–12 h before reuse in the next cycle for the best result.  相似文献   

8.
Three extraction systems including shaking, ultrasonic and microwave-assisted extraction were evaluated. Water and phosphate buffer were tested for the extraction of arsenic compounds in polluted soil, describing the water-soluble or plant-available fraction. The stabilities and recoveries of various arsenic species indicated that no obvious changes of species occurred during the extraction process. The raw extracts were cleaned up by C18 cartridge before analysis. Having optimized the extraction conditions, the arsenic species in polluted soil and ore from the different pollution sources were extracted by microwave-assisted extraction with 0.5 M phosphate buffer as extractant. Arsenic species were quantitatively determined by high performance liquid chromatography on-line coupled with hydride generation atomic fluorescence spectrometry (HPLC-HG-AFS). As(III) and As(V) were the major arsenic species in the polluted soil samples resulting from irrigation by waste water. AsV was the only form found in the rotten ore sampled in mining area. During the extraction process, the recoveries of spiked As(III), As(V), DMA(V) and MMA(V) were 85.4 ± 7.2%, 80.2 ± 6.7%, 101.6 ± 6.7% and 98.8 ± 9.1%, respectively, showing that most water-soluble arsenic could be measured.  相似文献   

9.
In this paper we discuss the use of Raman spectroscopy for characterising polymers both in the laboratory and also in-situ at the production line. We show how polymer crystallinity can be followed during extrusion and drawing, and describe the compositional analysis of cross-linked acrylic terpolymers in a polymerisation reactor. We also discuss problems which can arise such as sample fluorescence from moving polymers, distortion of relative band intensities due to chromatic aberration, and sampling difficulties with turbid solutions.  相似文献   

10.
A method for the identification of toxic compounds in industrial wastewater is presented, consisting of sequential solid phase extraction (SPE), fractionation by HPLC and GC-MS for compound identification. All analytical steps are accompanied by an automated detection of the aquatic toxicity by luminescence inhibition of Vibrio fischeri, which helps to reduce the large number of samples and subsamples that have to be processed by exluding those without toxic effects. The advantages of this procedure in comparison to previous methods of toxicity directed water analysis are discussed. The procedure was successfully applied to various samples of tannery wastewater, showing that benzothiazoles account for the major toxicity of tanyard wastewater. For very polar wastewater constituents, such as in beamhouse wastewaters, the use of LC-MS/MS for the final compound identification is suggested. Received: 25 September 1998 / Revised: 20 November 1998 / Accepted: 26 November 1998  相似文献   

11.
12.
A method for the identification of toxic compounds in industrial wastewater is presented, consisting of sequential solid phase extraction (SPE), fractionation by HPLC and GC-MS for compound identification. All analytical steps are accompanied by an automated detection of the aquatic toxicity by luminescence inhibition of Vibrio fischeri, which helps to reduce the large number of samples and subsamples that have to be processed by exluding those without toxic effects. The advantages of this procedure in comparison to previous methods of toxicity directed water analysis are discussed. The procedure was successfully applied to various samples of tannery wastewater, showing that benzothiazoles account for the major toxicity of tanyard wastewater. For very polar wastewater constituents, such as in beamhouse wastewaters, the use of LC-MS/MS for the final compound identification is suggested.  相似文献   

13.
We briefly describe a nonclassical nonlinear thermodynamic theory with statistical foundations. This statistical approach is based on a generalization to arbitrary nonequilibrium conditions of the Gibbs ensemble algorithm, the so-called nonequilibrium statistical operator method, which can be considered to be encompassed within the scope of Jaynes' predictive statistical physics. This emerging formalism is used to provide a study of the technoindustrial process of thermal stereolithography (or infrared-laser-induced rapid prototyping). The experimental results are interpreted and the technical requirements fundamental for the success of the process are pointed out. © 1997 John Wiley & Sons, Inc. Int J Quant Chem 65 : 277–285, 1997  相似文献   

14.
The problem of correcting EXAFS spectra by the core level width is discussed. A method of correcting experimental EXAFS spectra is developed. An iteration algorithm for solving the integral equation is proposed. This method has a number of advantages over other methods, namely, high stability against statistical error and fast convergence. Model numerical calculations are performed. An example is the EXAFS spectrum of polycrystalline Pd for which the broadening effect is significant. Translated fromZhumal Struktumoi Khimii, Vol. 39, No. 6, pp. 1018–1024, November–December, 1998.  相似文献   

15.
Agarose gel electrophoresis (AGE) has been used extensively for characterization of pure nanomaterials or mixtures of pure nanomaterials. We have evaluated the use of AGE for characterization of Ag nanoparticles (NPs) in an industrial product (described as strong antiseptic). Influence of different stabilizing agents (PEG, SDS, and sodium dodecylbenzenesulfonate), buffers (TBE and Tris Glycine), and functionalizing agents (mercaptosuccinic acid (TMA) and proteins) has been investigated for the characterization of AgNPs in the industrial product using different sizes‐AgNPs standards. The use of 1% SDS, 0.1% TMA, and Tris Glycine in gel, electrophoresis buffer and loading buffer led to the different sizes‐AgNPs standards moved according to their size/charge ratio (obtaining a linear relationship between apparent mobility and mean diameter). After using SDS and TMA, the behavior of the AgNPs in the industrial product (containing a casein matrix) was completely different, being not possible their size characterization. However we demonstrated that AGE with LA‐ICP‐MS detection is an alternative method to confirm the protein corona formation between the industrial product and two proteins (BSA and transferrin) maintaining NPs‐protein binding (what is not possible using SDS‐PAGE).  相似文献   

16.
Ambient concentrations of volatile organic compounds (VOCs) were measured using passive sampling technique at 49 sampling points in Kocaeli, an important industrial city in Turkey. Air samples were analyzed using thermal desorption (TD) and gas chromatography/flame ionization detectors (FID). Concentrations of benzene, toluene, ethylbenzene, m/p-xylenes, and o-xylene (BTEX), 1,3,5-trimethylbenzene, n-propylbenzene, 3-ethyltoluene, and 4-ethyltoluene were investigated to determine their spatial distribution and source apportionment. Concentrations of ΣBTEX ranged from 3.7 to 335.5 μg/m3. Among all the VOC species, m/p-xylene and toluene have the highest concentration. The spatial distributions for BTEX concentrations showed characteristic patterns: high concentrations were typically found along major roads, city centres, and near industrial plants. Pollution sources potentially affecting concentrations were identified using statistical analyses. The results of factor analysis indicated that vehicle exhaust and industrial activity were the predominant emission sources of the VOCs.  相似文献   

17.
Biotransformation processes have become industrially important in recent years as routes to the manufacture of high value chemical intermediates. However, measurements of key process features and analyte concentrations during these processes are still typically carried out using off-line analysis methods. Vibrational spectroscopic techniques have been extensively utilised for the monitoring and control of a variety of industrial processes. Despite the techniques success with a range of challenging biological matrices, including fermentation and cell culture systems, application of this approach to biotransformation systems has been limited. In the present study the potential of mid infrared spectroscopy to monitor an industrially relevant de-racemization biotransformation process has been investigated. This process presents a number of difficulties due to the optically challenging sample media, close structural similarities and stoichiometric relationship between the key analytes of interest. A PLS model based on the mid infrared spectra obtained during three replicates of the biotransformation process was constructed. In order to ensure that co-linearity within the system had been adequately addressed the spectral contributors to the model were examined. External validation of the constructed model was achieved by challenging the model with two previously unseen replicates of the process. The constructed model was able to predict the concentrations of two key analytes in various samples from these unseen replicates without the requirement for any time consuming sample pre-treatment stages, thus demonstrating the feasibility of near real-time mid infrared monitoring of such an industrial de-racemization biotransformation process.  相似文献   

18.
The surface topography and elemental composition of the near-surface layers of a reduced passivated catalyst for ammonia synthesis have been studied on a scanning electron microscope in the initial state and after high-temperature oxygen treatment as well as removal of the alkali promoter.
CA-IB , .
  相似文献   

19.
The influence of industrial reaction conditions on the kinetics of the polycondensation of polyamides is discussed. For analysis reasons the overall process was subdivided into individual kinetic phases. It will be shown that the basic features of the reaction rate in the final reaction stage can be explained assuming second order kinetics combined with a superposed reaction equilibrium. The influence of non-stoechiometry on the reaction rate is also demonstrated.  相似文献   

20.
许雯  任鹏飞  张欣然 《化学通报》2023,86(4):458-464,450
由于人为活动和气候变化,蓝藻水华污染已成为全球性环境问题。水华发生时藻类产生的毒性代谢物蓝藻多肽大量释放至水中,对生态系统和人类健康造成风险。本文系统梳理了包含微囊藻毒素在内的6种典型蓝藻多肽的浓度水平和毒性,并探讨了蓝藻多肽的光化学行为。结果显示,蓝藻多肽的浓度水平一般处于μg/L范围,其主要毒性位点为肝、肾和神经系统,致毒浓度LC50在μmol/L范围。蓝藻多肽以间接光解为主,半衰期长短与蓝藻多肽本身的结构和所含的氨基酸基团种类以及环境水体pH大小等有关。本研究为解析蓝藻多肽的环境影响和环境归宿提供参考。  相似文献   

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